Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01D—HARVESTING; MOWING
  • A01D34/00—Mowers; Mowing apparatus of harvesters
  • A01D34/006—Control or measuring arrangements
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01D—HARVESTING; MOWING
  • A01D34/00—Mowers; Mowing apparatus of harvesters
  • A01D34/01—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus
  • A01D34/412—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters
  • A01D34/63—Mowers; Mowing apparatus of harvesters characterised by features relating to the type of cutting apparatus having rotating cutters having cutters rotating about a vertical axis
  • A01D34/82—Other details
  • A01D34/828—Safety devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K28/00—Safety devices for propulsion-unit control, specially adapted for, or arranged in, vehicles, e.g. preventing fuel supply or ignition in the event of potentially dangerous conditions
  • B60K28/10—Safety devices for propulsion-unit control, specially adapted for, or arranged in, vehicles, e.g. preventing fuel supply or ignition in the event of potentially dangerous conditions responsive to conditions relating to the vehicle 

Definitions

• the present invention relates generally to electrical control circuits for a lawn and garden tractor or similar vehicle having a controllable power-take-off (PTO) system, and more particularly relates to an override system for establishing an override condition whereby the operator may operate the PTO while the vehicle is traveling in reverse.
• PTO power-take-off
• Lawn tractors, mowing machines, and similar vehicles such as snow blowers, sweepers, and leaf blowers having PTO driven attachments are well known.
• Such machines generally include a magneto operated internal combustion (IC) engine for driving the machine and a controllable power-take-off (PTO) for transferring power to an attachment or implement, such as the cutting unit of a lawn and garden tractor.
• IC internal combustion
• PTO controllable power-take-off
• an attachment or implement such as the cutting unit of a lawn and garden tractor.
• Various override systems have been proposed for this purpose, but many are inconvenient and difficult to operate. Providing an override system that is convenient, safe, reliable, and relatively simple to incorporate into existing engine control circuitry has been heretofore difficult to achieve.
• Override control circuits adapted for use with a riding lawn mowing vehicle having a conventional magneto operated internal combustion (IC) engine.
• the control circuits are adapted to provide an override condition for selectively allowing the PTO (and associated cutting blades) of the vehicle to operate when the vehicle is traveling in reverse.
• the control circuits are responsive to input from a key actuated ignition switch, a manually activated override switch, a vehicle reverse switch, and a power-take-off (PTO) switch.
• PTO power-take-off
• control circuit is adapted to disable an electric PTO clutch if the vehicle is placed in reverse with the PTO engaged and without the override condition having been established.
• the override condition is maintained when the vehicle transitions between reverse and forward operation direction. This means the vehicle can be repeatedly shifted back and forth between forward and reverse without interrupting the override condition.
• the override condition is also maintained if the operator transitions the PTO between an engaged and disengaged condition subsequent to the override condition having been established.
• Fig. 1A is a circuit schematic illustrating a manual PTO override circuit in accordance with an embodiment of the present invention
• Fig. IB is a circuit schematic illustrating an electric PTO override circuit in accordance with an alternative embodiment of the present invention.
• DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0009] With reference to the drawings, Figs. 1A and IB depict a pair of override control circuits in accordance with exemplary embodiments of the present invention. Each circuit is comprised of readily available components. Although the circuits are similar is many respects, important differences between the circuits are noted where such differences are important for understanding the scope of the present invention.
• both circuits are adapted to provide an override condition for allowing PTO operation when the vehicle is operating in a reverse direction.
• the circuit of Fig. 1A is referred to as a "manual PTO" circuit because it is adapted to kill the engine (and subsequently disable the PTO) if reverse operation is selected when the PTO switch 20 is engaged and without the override condition having been established.
• the circuit of Fig. IB is referred to as an "electric PTO" circuit because it is adapted to disable an electric PTO clutch 60 (and subsequently disable the PTO) if reverse operation is selected when the PTO switch 20 is engaged and without the override condition having been established.
• both circuits include a two-position PTO switch 20.
• the PTO switch 20 is shown in the off position.
• the PTO switch 20 allows the operator to selectively activate and deactivate the vehicle power-take-off (PTO) so as to control the associated implements, i.e., the cutting blades (not shown), via the PTO switch 20.
• PTO vehicle power-take-off
• the PTO switch 20 is in the form of a two-pole switch
• the PTO switch 20 is in the form of a three-pole switch, wherein the middle pole is connected to a second general purpose relay 64 for controlling the electric PTO clutch 60.
• Both circuits incorporate a reverse switch 40 for selectively operating the vehicle in a reverse or forward direction, and a first general purpose relay 42 operatively associated between the PTO switch 20 and reverse switch 40.
• the override control circuits of Figs. 1A, IB are adapted for use with a riding lawn mowing vehicle having a conventional magneto operated internal combustion engine (not shown).
• Both circuits incorporate a multi- position key actuated ignition switch 8 having an input terminal B connected to a source of electrical power, such as battery 4.
• the ignition switch 8 includes an OFF position, a RUN1 position, a RUN2 position, and a START position.
• the override condition of the present invention is predicated on the ignition switch 8 being placed in either the RUN1 or RUN2 position.
• many different ignition switch configurations could be used to achieve the same results.
• a complete circuit is provided via ignition switch terminals M and G, thereby connecting the magneto 10 to ground and preventing the engine from operating.
• ignition switch 8 is moved to the START position, a complete circuit is provided between starter unit 2 and battery 4 (assuming brake switch 14 is ON and PTO switch 20 is OFF), thereby energizing solenoid 6 via battery 4 so as to actuate starter 2 and start the engine.
• ignition switch 8 is adapted to move to either the RUN1 or RUN2 position. If the operator should leave the operator seat when the engine is running and the brake switch 14 is OFF, seat switch 12 will create an uninterrupted current path between the magneto 10 and ground (via the upper pole of brake switch 14), thereby killing the engine.
• the circuits include an override switch 80 for selectively activating the override condition.
• the override switch 80 comprises a manually operated twist-and-pull magnetic switch operatively associated with an electromagnetic coil 81.
• the override switch 80 and electromagnetic coil 81 are connected to ignition switch terminal Al.
• the electromagnetic coil 81 is continuously energized via terminal Al whenever the ignition switch 8 is placed in the RUN1 or RUN2 position. Assuming the engine has been started and the ignition switch 8 has been placed in the RUN1 or RUN2 position, the override condition may be achieved once the operator physically activates the override switch 80. [0016] Once the operator has manually activated override switch 80, an electromagnetic force induced by electromagnetic coil 81 (assuming coil 81 is energized by terminal Al) is of sufficient magnitude to sustain the override switch 80 in the activated (i.e., closed) position.
• the electromagnetic force from the electromagnetic coil 81 is sufficient to sustain the override switch 80 in the activated position once the override switch has been manually (i.e., physically) activated by the operator, it is not of sufficient magnitude to activate or trigger the override switch by itself. Rather, the override switch is initially triggered by a physical input (i.e., twist and pull) from the operator.
• a physical input i.e., twist and pull
• switches including, but not limited to, digital flip-flops, may be used to achieve the same results.
• reverse switch 40 is isolated from PTO switch 20, allowing the operator to repeatedly open and close the reverse switch 40 without interrupting the continuous operation of the PTO. Since the override switch 80 is sustained in the closed position by the energized electromagnetic coil 81, there is no requirement for the operator to actuate the override condition each time the vehicle is put into reverse to facilitate mowing in reverse. In this way, once the override switch is engaged and the override condition is achieved, the vehicle can be repeatedly shifted back and forth through FORWARD and REVERSE positions without interrupting or re-setting the override condition.
• the vehicle can be placed in reverse with the PTO ON without having to reactivate the override switch 80 each time the vehicle is placed in reverse. If during operation the operator should decide to disable the override condition, the operator may disengage the override switch 80 and return to the non-override mode of operation.
• the override condition of the present invention is independent of the status of the PTO switch 20. This means that once the override switch 80 is activated, the operator can repeatedly cycle the PTO switch 20 between the ON and OFF positions without affecting or interrupting the override condition.
• the electric PTO circuit of Fig. IB includes a second general purpose relay 64 and associated electric PTO clutch 60. As shown in Fig.
• second relay 64 will remain energized even if the operator subsequently activates the override switch 80. Second relay 64 will remain energized due to a self-feeding current circulating between the alternator/afterfire solenoid 66 and ground via relay 64 (coil), the closed middle pole of PTO switch 20, and the activated terminals of relay 64. In order to deactivate second relay 64 and thus restore PTO operation, the operator must first turn the PTO switch OFF so as to open the middle pole of PTO switch 20 and interrupt the self-feeding current path.
• PTO operation may be re-established when the operator reengages the PTO switch 20, assuming the override switch 80 remains closed as the vehicle is traveling in reverse.
• the foregoing feature improves operator safety by requiring the operator to intentionally toggle the PTO switch off and then on again if PTO operation is desired when reverse operation is selected prior to the override switch having been activated.
• the operator may manually de-activate the override switch 80 by physically returning the override switch 80 to its original (i.e., open) position.
• the override switch (which may, for example, be spring loaded) returns to its default (i.e. open) position, thereby interrupting the flow of current to first relay 42 and thus releasing the override condition.
• the override switch 80 As shown in Figs. 1A and IB, suppose the operator leaves the operator seat when the override switch 80 is activated. An open circuit at seat switch 12 interrupts the current path through the electromagnetic coil 81, thereby releasing the override switch 80.
• first relay 42 is deactivated, thus disabling the override condition.
• the operator seat switch 12 is employed to release the override condition, many other switching means could also be used to release the override condition, such means being well-known in the art.
• the override condition is also released if the operator turns the ignition switch 8 to the OFF position.
• the electromagnetic coil 81 is deactivated, thereby releasing the magnetic override switch 80 and thus disabling the override condition.
• the electric PTO circuit further includes an array of electrical leads 107 which may be connected in a manner known in the art to a series of dashboard lights or monitors to notify the operator of the operational status of the respective components as shown, thereby further improving operator convenience.
• each of the control circuits of the present invention there is no requirement for the operator to actuate the override condition each time the vehicle is put into reverse to facilitate mowing in reverse. Rather, once the override switch 80 is engaged and the override condition is achieved, the vehicle can be repeatedly shifted back and forth between forward and reverse direction without disabling the PTO or interrupting the override condition.
• the override condition is independent of the status of the PTO switch 20. This means that once the override switch 80 is activated, the operator can repeatedly cycle the PTO switch 20 between the ON and OFF positions without affecting or interrupting the override condition.
• the override condition is maintained even if the operator desires to temporarily turn the PTO OFF (for example, when crossing a road or driveway). PTO operation can be subsequently restored by simply turning the PTO switch ON, without having to re-set or reactivate the override condition.
• PTO operation can be subsequently restored by simply turning the PTO switch ON, without having to re-set or reactivate the override condition.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Environmental Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Harvester Elements (AREA)

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• 2005
  • 2005-02-16 WO PCT/US2005/004782 patent/WO2005081826A2/en active Application Filing
  • 2005-02-16 EP EP05713595.6A patent/EP1720400B1/de not_active Expired - Fee Related
  • 2005-02-16 US US10/590,166 patent/US7523796B2/en active Active

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